Simply visit pwa.kiwix.org in a desktop Chromium browser. Read more after the demo:
Demo-OPFS-all-features.mp4
See also: [ Install PWA and use OPFS in Chrome for Android ] [ Install PWA on Firefox for Android ]
Chromium desktop browsers (Chrome, Edge, Brave, etc.) support all the features shown in this demo, i.e. adding files to the OPFS, downloading directly into the OPFS, deleting files, and exporting them to the user-visible file system. Firefox desktop, and all Android browsers, supports all of these actions except exporting files. Firefox is currently limited to a maximum OPFS quota of 10 GB.
See also: [ Install PWA and use OPFS in Chrome for Android ] [ Install PWA on Firefox for Android ]